The 3rd Generation Partnership Project (3GPP) releases an evolved packet system (EPS) based on existing 2G and 3G networks. An EPS network includes an Evolved universal mobile telecommunication system territorial radio access network (E-UTRAN) and an evolved packet core network (EPC). During an early stage in construction of an EPS network, a carrier already has a mature circuit switched (CS) network and the EPS network processes only packet switched (PS) services. To protect an investment on the CS network and satisfy requirements on deployment policies of the EPS network, a carrier may use existing CS network devices to provide CS services. To satisfy the requirements, the 3GPP extends Gs interface functionality between a mobile switching center/visitor location register (MSC/VLR) and a serving GPRS support node (SGSN). An SGs interface between the MSC/VLR and a mobile management entity (MME) is defined on the EPC network. Based on the SGs interface functionality, the 3GPP specifies a circuit switched fallback (CSFB) technology and an SGs short message transmission (SMS over SGs) technology. The CSFB technology enables a user equipment (UE) covered by an E-UTRAN to fall back to a 2G/3G network CS domain to complete service processing over the E-UTRAN when the UE needs to process a CS voice service. The SMS over SGs technology enables a UE camping on the E-UTRAN to reuse existing CS domain devices to implement CS short message transmission.
To reduce deployment cost of a radio access network for a carrier, the 3GPP defines an idea of network sharing. That is, public land mobile networks (PLMN) of a plurality of carriers or a plurality of PLMNs of a carrier may share the same radio access network to provide radio communication services. For the CSFB technology and the SMS over SGs technology, carriers also raise a desire for CS domain network sharing, which mainly includes the following two scenarios. In one scenario, a traditional carrier upgrades the existing 2G/3G CS network to support the CSFB technology and the SMS over SGs technology. That is, a carrier may share its own plurality of PLMNs or share a PLMN of another carrier by signing a roaming protocol to provide the CS services for a UE camping on the E-UTRAN. In another scenario, a rising pure-PS service carrier may sign a protocol to lease the 2G/3G CS network from a traditional carrier to support the CSFB technology and the SMS over SGs technology.
In the CS domain network sharing scenario, a plurality of available PLMNs may provide the CS services for the same UE camping on an E-UTRAN. In a combined attach procedure or a combined tracking area update procedure, if a plurality of available PLMNs provide the CS services for the UE, the MME selects a suitable PLMN according to a PLMN reported by an evolved NodeB (eNodeB), location information of a tracking area where a UE is currently located, and a CS network selection policy of a carrier. Based on the selected PLMN and the location information of the tracking area where the UE is located, the MME assigns a corresponding CS domain location area identity (LAI) to the UE, and selects an associated MSC/VLR based on the LAI.
After successfully registering to a carrier's network, a terminal should display a name of the registered network to a user of the terminal. Currently, displaying of a network name is mainly based on two types of policies. In one type of policy, a network side directly sends a network name to a UE. In another type of policy, a network side does not perform configuration, and a UE displays a network name according to its own configuration. A network name sent by a network side includes a network name of a registered CS network sent by an MSC/VLR over an SGs interface. If the MSC/VLR sends a name of a registered CS network to an MME, the MME transparently transmits the network name to the UE.
In the CS domain network sharing scenario, a CS PLMN selected by the MME for the UE may be different from a home PLMN of the MME. That is, the network name of the registered CS network sent by the MSC/VLR over the SGs interface is different from the network name of the UE's currently registered PS network. As a result, after performing a CSFB service or an SMS over SGs service, the UE displays a different network name to the user, that is, displays the network name of the registered CS network to the user. For an E-UTRAN terminal user, user experience deteriorates. In other words, the currently displayed network name is not a registered network of the user, bringing high complaint risks to a carrier.
In addition, on the traditional 2G/3G network, a registered CS PLMN of the terminal may be different from a registered PS PLMN of the terminal. If the MSC/VLR sends a name of a registered CS network over the Gs interface, an SGSN forwards the network name to the terminal, similarly resulting in the inconsistency of a network name.